In the market of compact projector apparatuses, low-cost competition is very severe, so that, in order to reduce the cost and improve manufacturing efficiency, designers are required to reduce the number of parts of a product. Thus, the designers must consider realization of multiplexing effect of using the same parts for different purposes.
Further, in a compact projector apparatus, in order to lower the exhaust air temperature so as not to make the user of the apparatus unpleasant when he is exposed to the air discharged from the apparatus and to fulfill other objects, it is necessary to take measures to improve fluid-dynamical conditions of air expired from an exhaust fan within the apparatus. Also, in the design of a resin casing replacing an electroplated casing, a problem of shielding the components inside the casing must be solved.